"For the first time this year scientists used another test developed by the Memphis Zoo which analyzed Mei Xiang's levels of prostaglandin metabolite (a fatty acid) to narrow the window when she would give birth or experience a pseudopregnancy. Scientists at the Memphis Zoo performed the analysis and determined that if Mei Xiang were pregnant she would likely give birth during the last week of August. If she were not, her pseudopregnancy would have likely ended in early September."